title: Diaphragmatic function is preserved during severe hemorrhagic shock in the rat.
abstract: BACKGROUND
  Acute diaphragmatic dysfunction has been reported in septic and cardiogenic shock, but few data are available concerning the effect of hemorrhagic shock on diaphragmatic function. The authors examined the impact of a hemorrhagic shock on the diaphragm.
  
  
  METHODS
  Four parallel groups of adult rats were submitted to hemorrhagic shock induced by controlled exsanguination targeting a mean arterial blood pressure of 30 mmHg for 1 h, followed by a 1-h fluid resuscitation with either saline or shed blood targeting a mean arterial blood pressure of 80 mmHg. Diaphragm and soleus strip contractility was measured in vitro. Blood flow in the muscle microcirculation was measured in vivo using a Laser Doppler technique. Muscle proinflammatory cytokine concentrations were also measured.
  
  
  RESULTS
  Hemorrhagic shock was characterized by a decrease in mean arterial blood pressure to 34 ± 5 mmHg (-77 ± 4%; P< 0.05) and high plasma lactate levels (7.6 ± 0.9 mM; P < 0.05). Although tetanic tension of the diaphragm was not altered, hemorrhagic shock induced dramatic impairment of tetanic tension of the soleus (-40 ± 19%; P < 0.01), whereas proinflammatory cytokine levels were low and not different between the two muscles. Resuscitation with either blood or saline did not further modify either diaphragm or soleus performance and proinflammatory cytokine levels. The shock-induced decrease in blood flow was much more pronounced in the soleus than in the diaphragm (-75 ± 13% vs. -17 ± 10%; P = 0.02), and a significant interaction was observed between shock and muscle (P < 0.001).
  
  
  CONCLUSIONS
  Diaphragm performance is preserved during hemorrhagic shock, whereas soleus performance is impaired, with no further impact of either blood or saline fluid resuscitation.
authors.affiliation: From the Department of Pneumology and Medical Intensive Care and ER10, Hôpital Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris (APHP), Université Pierre et Marie Curie-Paris 6, Paris, France (S.C.); ER10 and UMR INSERM, Université Pierre et Marie Curie, Paris, France (M.L.D.); Department of Orthopedic Surgery, Hôpital de Bicêtre, APHP, and ER 3509, Université Paris Sud, Le Kremlin-Bicêtre, Paris, France (M.S.); Department of Emergency Medicine and Surgery, Hôpital Pitié-Salpêtrière, APHP, UMR INSERM 956 and Institute of Cardiometabolism and Nutrition, Université Pierre et Marie Curie-Paris 6 (M.-P.P.); Department of Emergency Medicine and Surgery, Hôpital Pitié-Salpêtrière, UMR INSERM 956 and Institute of Cardiometabolism and Nutrition, Université Pierre et Marie Curie-Paris 6 (B.R.); Department of Pneumology and Medical Intensive Care, Hôpital Pitié-Salpêtrière, and ER10, Université Pierre et Marie Curie (T.S.); UMRS INSERM 974-CNRS 7215, Institut de Myologie, Université Pierre et Marie Curie-Paris 6 UM76, Paris, France (C.C.); and Department of Pneumology and Medical Intensive Care, Hôpital Pitié-Salpêtrière, and UMR INSERM 974-CNRS 7215, Université Pierre et Marie Curie-Paris 6 (A.D.).
authors.forename: Serge
authors.initials: S
authors.lastname: Carreira
authors.forename: Matthieu
authors.initials: M
authors.lastname: Lê Dinh
authors.forename: Marc
authors.initials: M
authors.lastname: Soubeyrand
authors.forename: Marie-Pierre
authors.initials: MP
authors.lastname: Poloujadoff
authors.forename: Bruno
authors.initials: B
authors.lastname: Riou
authors.forename: Thomas
authors.initials: T
authors.lastname: Similowski
authors.forename: Catherine
authors.initials: C
authors.lastname: Coirault
authors.forename: Alexandre
authors.initials: A
authors.lastname: Demoule
mesh_terms: D000818:Animals; D062186:Arterial Pressure / Q000502:physiology; D001784:Blood Gas Analysis; D016207:Cytokines / Q000378:metabolism; D003964:Diaphragm / Q000098:blood supply / Q000503:physiopathology*; D005440:Fluid Therapy; D019344:Lactic Acid / Q000097:blood; D008297:Male; D008833:Microcirculation / Q000502:physiology; D009119:Muscle Contraction / Q000187:drug effects; D018482:Muscle, Skeletal / Q000098:blood supply / Q000187:drug effects; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D051381:Rats; D017208:Rats, Wistar; D060888:Real-Time Polymerase Chain Reaction; D012039:Regional Blood Flow / Q000502:physiology; D012151:Resuscitation; D012771:Shock, Hemorrhagic / Q000503:physiopathology* / Q000628:therapy; D014882:Water-Electrolyte Balance
chemical_list: D016207:Cytokines; D012333:RNA, Messenger; D019344:Lactic Acid